Plate Tectonics

1
Plate Tectonics of the Lesser Antilles
By Justin Howard
http//www.ngdc.noaa.gov/mgg/image/2minsurface/13
50/45N090W.jpg
2
Lesser Antilles

• Location
• The chain of islands wrapped around the eastern
  end of the Caribbean Sea on the boundary with the
  Atlantic ocean.
• Islands
• The US Virgin Islands, British Virgin Islands,
  Anguilla, Saint Kitts, Nevis, Antigua, Barbuda,
  Saint Vincent, Barbados, St. Lucia, Dominica,
  Guadeloupe, Montserrat, Grenadines, Grenada,
  Trinidad, Tobago, The Netherlands Antilles, the
  island off the coast of Venezuela, and Aruba.

http//www.sitesatlas.com/Maps/Maps/309.htm
3
Tectonic Plates of Earth
http//www.sitesatlas.com/Maps/Maps/309.htm

• Tectonic Plate
• A piece of the Earths lithosphere, or crust.

4

• Plate Tectonics
• The theory developed to explain the phenomena of
  continental drift.
• The outermost part of the Earths interior is
  made up of two layers.
• The Asthenosphere
• The region located beneath the lithosphere
  between 100 and 700 Km below the
  surface.
• The Lithosphere
• The outermost solid shell of Earth between the
  uppermost layer of mantle and the crust.
• Plate Boundaries
• Transform Boundaries
• The grinding of two plates along transform
  faults, where the rock fracture is
  caused by lateral movement of two surfaces.
• Divergent Boundaries
• The sliding of plates past each other.
• Convergent Boundaries
• The sliding of two plates toward each other and
  one is forced under the other.

5
Plate Boundaries
http//www.wordiq.com/definition/ImageTectonic_pl
ate_boundaries.png
6
Plate Tectonics of the Lesser Antilles

• Consists of Convergent boundaries where the
  Atlantic and Caribbean plates meet.
• The rate of subduction is on average 1 inch per
  year.
• Seventeen volcanoes have been active in the last
  10,000 years, the Holocene, in the West Indies.
• Active Volcanoes include
• Kick-Em-Jenny
• Soufriere Hills

http//www.mount-pelee.com/arcvolc.htm
7

• The chain of volcanoes present at the mid-oceanic
  ridge is a result of the subducted Cocos Plate
  beneath the west edge of the Caribbean Plate.

http//volcano.und.nodak.edu/vwdocs/volc_images/no
rth_america/west_indies.html
8
A Cross-Sectional View of the Lesser Antilles
Convergent Boundary
http//www.mount-pelee.com/arcvolc.htm
9
Results of Tectonic Activity in the British
Virgin Islands Virgin Gorda
Justin Howard
10
70 million years ago, during the Tertiary, magma
accumulated on the lava layers of the Caribbean
seabed forming huge sections of granite.
Justin Howard
11

• It wasnt until 15-25 million years ago that
  the granite created under water was exposed by
  faulting and uplifting. That granite, pictured
  here, has since been weathered (largely by acid
  rain). This explains the rough, flaking surface.

Justin Howard
Justin Howard
12
Bibliography

• Howard, Justin. Personal Photos, Virgin Gorda,
  BVI. 2004.
• Press, Frank et al. Understanding the Earth.
  Freeman Press, New York, NY. 2004.
• http//www.ngdc.noaa.gov/mgg/image/2minsurface/135
  0/45N090W.jpg
• http//www.mount-pelee.com/arcvolc.htm
• http//www.sitesatlas.com/Maps/Maps/309.htm
• http//www.wordiq.com/definition/ImageTectonic_pl
  ate_boundaries.png
• http//www.thebathsbvi.com/map.htm
• http//volcano.und.nodak.edu/vwdocs/volc_images/no
  rth_america/west_indies.html